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๐งฌ CELL: THE BUILDING BLOCK OF
LIFE (Class 9 NCERT)
๐งฌ 1. CELL = BASIC UNIT OF LIFE
Living Organisms โ โผ Cells โ โโโโโโโดโโโโโโ โผ โผ Unicellular Multicellular (Bacteria) (Plants, Animals)
๐งฌ Cell Theory
All Living Organismss โ โผ Made of Cells โ โผ Cell = Basic Structural & Functional Unit of Life โ โผ New Cells Arise From Pre-existing Cells
๐งฌ 2. HOW DO WE STUDY CELLS?
Human Eye Resolution = 0.1 mm โ Cannot See Cells โผ Microscope โ โโโโโโดโโโโโโ โผ โผ Light Electron Microscope Microscope
๐งฌ Scientists
Scientist Contribution
Robert Hooke (1665) First observed cells in cork
Camillo Golgi Discovered Golgi Apparatus
Schleiden Plants made of cells
Schwann Animals made of cells
Virchow Cells arise from pre-existing cells
๐งฌ 3. CELL MEMBRANE
Cell Membrane โ โผ Selectively Permeable โ โโโโโโดโโโโโโ โผ โผ Allows Blocks Some Others
Structure
Protein โ Lipid Bilayer โ Protein
Functions
โ
Protects cell
โ
Controls entry & exit
โ
Cell communication
๐งฌ 4. OSMOSIS & DIFFUSION
Diffusion
High Concentration โ โผ Low Concentration
๐งฌ 6. TYPES OF CELLS
Cells โ โโโโโโโโโโโโโโโ โผ โผ Prokaryotic Eukaryotic
Prokaryotic
Bacteria โ No True Nucleus No Membrane Organelles
Eukaryotic
Plant & Animal Cells โ True Nucleus Membrane Organelles
Quick Comparison
Feature Prokaryotic Eukaryotic
Nucleus โ
โ
Organelles โ
โ
Size Small Large
Example Bacteria Plants, Animals
๐งฌ 7. CELL ORGANELLES
๐งฌ Nucleus
Nucleus โ Controls Cell โ Contains DNA
Parts
Nucleus โ
โโ Nuclear Membrane โโ Nucleolus โโ Chromatin ๐งฌ Ribosomes Ribosomes โ Protein Synthesis Remember
โ
Protein Factory
Endoplasmic Reticulum (ER) ER โ โโโ RER โ โ โ Protein โ Synthesis โ โโโ SER โ Fat & Hormone Synthesis ๐งฌ Golgi Apparatus ER โ โผ Golgi Apparatus โ โผ Packaging โ โผ Transport Function
โ
Cell's Post Office
Colour Pigments โ โผ Red/Orange/Yellow
Leucoplast ๐งฌ
Storage โ โผ Starch/Oil/Protein
๐งฌ 9. VACUOLE
Vacuole โ Stores Water Minerals Waste Food
Function
โ
Maintains Turgidity
โ
Keeps plant upright
๐งฌ 10. PLANT CELL vs ANIMAL CELL
Feature Plant Cell ๐งฌ Animal Cell ๐งฌ
Cell Wall โ
โ
Chloroplast โ
โ
Vacuole Large Small
Shape Fixed Irregular
๐งฌ 11. CELL DIVISION
Cell Division โ โโโโโโดโโโโโโ โผ โผ Mitosis Meiosis
Mitosis
1 Parent Cell โ โผ Cell Division โ โผ 2 Identical Cells
Uses
โ
Growth
โ
Repair
โ
Replacement
Meiosis
1 Parent Cell โ โผ Two Divisions โ โผ 4 Daughter Cells
Uses
โ
Gamete Formation
โ
Genetic Variation
๐งฌ 12. CELL DIVISION SUMMARY
Mitosis Meiosis
2 Cells 4 Cells
Identical Different
Growth Reproduction
Body Cells Gametes
